<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="root"></div>

    <script src="https://unpkg.zhimg.com/react@17.0.2/umd/react.development.js"></script>
    <script src="https://unpkg.zhimg.com/react-dom@17.0.2/umd/react-dom.development.js"></script>
    <script src="https://unpkg.zhimg.com/@babel/standalone/babel.min.js"></script>

    <script type="text/babel">
        class Time extends React.Component {

            state = {
                date: new Date()
            }

            componentDidMount() {
                setInterval(() => {
                    this.setState({
                        date: new Date()
                    })
                }, 1000);
            }

            render() {
                return (
                    <div>
                        <h1>hello</h1>
                        <input type="text" /><br/><br/>
                        <span>
                            现在时间：{this.state.date.toTimeString()}
                            <input type="text" />
                        </span><br/><br/>
                    </div>
                )
            }

        }
       
        ReactDOM.render(<Time />, document.getElementById('root'))
    </script>
</body>
</html>